Question

what is the complementary mrna sequence for a dna sequence of tag, cat, aat?

Explanation:

Step1: Recall base - pairing rules

In DNA - mRNA transcription, \(A\) (adenine) pairs with \(U\) (uracil) in mRNA, \(T\) (thymine) pairs with \(A\) (adenine), \(G\) (guanine) pairs with \(C\) (cytosine), and \(C\) (cytosine) pairs with \(G\) (guanine).
For the DNA triplet \(TAG\):
\(T
ightarrow A\), \(A
ightarrow U\), \(G
ightarrow C\), so it transcribes to \(AUC\).

Step2: Transcribe the second triplet

For the DNA triplet \(CAT\):
\(C
ightarrow G\), \(A
ightarrow U\), \(T
ightarrow A\), so it transcribes to \(GUA\).

Step3: Transcribe the third triplet

For the DNA triplet \(AAT\):
\(A
ightarrow U\), \(A
ightarrow U\), \(T
ightarrow A\), so it transcribes to \(UUA\).

Answer:

AUC GUA UUA